Many Ultraviolet devices advertised recently claims to kill the SARS-Cov-2 Coronavirus. But what is the reality? Are they effective in killing the Coronavirus?. This is only a short topic just to understand the technology and basic facts.
SARS-Cov-2 virus is responsible the Coronavirus Disease 2019 or Covid-19. The Ultraviolet radiation is a known disinfectant for air, water and non-porous surfaces. The Ultraviolet – C (UVC) radiation is used to reduce the spread of bacteria. UVC Lamps are therefore called as “Germicidal Lamps”.
The UVC radiation is effective in destroying the outer protein coating of SARS-Coronavirus. SARS-Coronavirus and the current SARS-Cov-2 are different. Experts say that the UVC radiation may also be effective in inactivating the SARS-Cov-2 virus. There are not much published data regarding the effectiveness, wavelength, dose and duration of UVC radiation to inactivate SARS-Cov-2 virus.
What is Ultraviolet (UV) Radiation?
UV Radiation is basically an electromagnetic wave energy. The Sun also emits UV Rays. The wavelength of UV radiation is shorter than that of the visible light. The full spectrum of UV Radiation is divided into three UVA, UVB and UVC having different wavelengths.
UV-A (UVA) is having a wavelength of 315 to 400nm, UV-B (UVB) has 280 to 315nm and UV-C (UVC) has 100 to 280nm wavelength. Due to its shortest wavelength, the UVC rays in the Sunlight get blocked by earth’s atmosphere before reaching the surface.
UVA is not effective in penetrating the pathogens whereas UVB which is most hazardous can penetrate deep into the skin and eyes. So, care must be taking while working with UVB radiation. UVC is not much dangerous and at the same time can penetrate pathogens. Long term exposure of UVC creates skin burn or irritation and hence must be carefully handled.
UVGI and UVC
The Ultraviolet Germicidal Irradiation (UVGI) solutions have the ability to kill virus but one must be careful in selecting the right solution. Experts say that there is no known pathogen which cannot be killed by UVGI. But since UVC is not found in nature, pathogens have not developed resistance to it.
The latest UVGI devices are all powered by UVC, which can be used to disinfect surfaces of spaces such as hotels, offices, restaurants, hospitals etc. There are portable hand sanitizing devices available in market.
There are some limitations to how effective UVC radiation can be, for inactivating viruses. Only a direct exposure to UVC radiation can inactivate the virus. The devices sold for home use are of low dose and hence may require longer exposure time.
Read more about UV Lamps, UVC Radiation and Coronavirus here
Disclaimer: Information collected from various sources
Watch a short video by WHO on the use of UV Lamps and Covid-19
